The analysis included adults aged 19 years or older and examined three mental health indicators. Elevated depressive symptoms were defined as a score of at least 10 on the Patient Health Questionnaire-9, or PHQ-9, while elevated anxiety symptoms were defined as a score of at least 10 on the seven-item Generalized Anxiety Disorder-7, or GAD-7. Suicidal ideation referred to whether a participant had experienced thoughts of suicide during the previous 12 months. The study therefore focused on the associations between dietary intake categories and the measured indicators, rather than demonstrating any effect of changing diet or nutrient intake on mental health.

Dietary exposure was assessed with a single 24-hour dietary recall. Separately surveyed supplement quantities were not added to the estimates, meaning the exposure analysis concerned food-derived nutrient intake rather than total intake including supplements. High magnesium intake was defined as at least 350 mg per day for men and at least 250 mg per day for women. High omega-3 intake was defined as at least 1.5 g per day. Because the study used one day of dietary reporting, the researchers cautioned that a single recall may not accurately represent usual intake.

The investigators used survey-weighted logistic regression to account for the complex design of the national examination, incorporating survey strata, clusters and integrated health and nutrition weights. The models included 13 covariates. For high omega-3 intake, the adjusted odds ratio for elevated depressive symptoms was 0.833, with a 95% confidence interval of 0.556–1.249 and p = 0.375. The corresponding adjusted odds ratios were 0.929 for elevated anxiety symptoms, with a 95% confidence interval of 0.631–1.367 and p = 0.705, and 0.822 for suicidal ideation, with a 95% confidence interval of 0.557–1.215 and p = 0.324. All 12 primary adjusted tests—including analyses of magnesium intake, joint intake and the interaction between magnesium and omega-3 intake—had p values greater than 0.05. These confidence intervals were wide, indicating imprecision in the estimated associations.

An exploratory analysis also assessed symptom-score trends across quartiles of nutrient intake. The omega-3–PHQ-9 trend had a nominal p value of 0.026, but its approximate Benjamini–Hochberg-adjusted p value was 0.104 across four trend tests. Thus, the exploratory finding was not statistically significant after the multiple-testing adjustment. The cross-sectional design cannot establish whether dietary intake preceded the mental health indicators or whether mental health was related to eating habits, while the one-day dietary assessment further limits conclusions about usual nutrient exposure. The results do not show that magnesium or omega-3 intake improves mental health, and they do not establish that such intake has no relationship with mental health. Prospective studies with repeated dietary measurements could help clarify the direction and magnitude of these associations.

Subject of Research: Dietary magnesium and omega-3 intake in relation to mental health indicators among Korean adults

Article Title: Associations of dietary magnesium and omega-3 fatty acid intake with mental health indicators among Korean adults: a population-based cross-sectional study

Article References: Lee, H., & Choi, M. (2026). Associations of dietary magnesium and omega-3 fatty acid intake with mental health indicators among Korean adults: a population-based cross-sectional study. BMC Public Health. https://doi.org/10.1186/s12889-026-29827-3

Image Credits: AI Generated

DOI: 10.1186/s12889-026-29827-3

Keywords: dietary magnesium, omega-3 fatty acids, depressive symptoms, anxiety symptoms, suicidal ideation, mental health, dietary intake, Korean adults, cross-sectional study, Associations, dietary, magnesium